Cinta had revealed herself to him as an entirely new being.

He would never have suspected such energy of character, such passionate vehemence, in his sweet, obedient, little wife.

She must have some counselor who was encouraging her complaints and making her speak badly of her husband.
And he fixed upon Don Pedro, the professor, because there was still deep within him a certain dislike of the man since the days of his courtship.

Besides, it offended him to see him in his home with a certain air of a noble personage whose virtue served as foil for the sins and shortcomings of the master of the house.
The professor evidently considered Ferragut on a level with all the famous Don Juans,--liberal and care-free when in far-away homes, punctilious and suspiciously correct in his own.
"That old blatherskite!" said Ulysses to himself, "is in love with Cinta.

It is a platonic passion: with him, it couldn't be anything else.